Apparatus for and method of stripping containers from metal working punches

ABSTRACT

As a punch is removed from a metal working die during a return stroke, a knock-out member remains extended while the punch is withdrawn from a shell or can body thereby stripping the can body from the punch. The knock-out member is then retracted into the punch. By providing a round trip camming mechanism in combination with a geared knock-out drive mechanism, the knock-out stroke for the knock-out drive is substantially equal to the height of the can and the knock-out member is retracted into the punch before the return stroke is completed.

United States 1 Patent [1 1 Duhan [s41 APPARATUS FoR AND METHOD OFSTRIPPING CONTAINERS FROM METAL WORKING PUNCHES [75] Inventor: F. Wm.Duhan, Philadelphia, Pa.

[73] Assignee: Crown Cork & Seal Company, Inc.,

Philadelphia, Pa.

22 Filed: Mareh4, 1971 [21] Appl.No.:121,059'

52 us. Cl 72/345 [51] Int. Cl. ..B2ld 45/00 [58] Field of Search..72/344, 345, 346, 361, 427

[56} Q 0 References Cited UNITED STATES PATENTS 398,229 2/1889 Chambers..72/345 3,270,544 9/1966 Maeder et al. .....72/345 3,423,985 1/1969Stolle ..72/348 3,402,591 9/1968 Maeder ..72/345 Jan. 23, 1973 FOREIGNPATENTS OR APPLICATIONS 703,340 3/1941 Gennany ..72/344 PrimaryExaminer-Richard J. Herbst Attorney-Woodcock, Washburn Kurtz &Mackiewicz [57] ABSTRACT As a punch is removed from a metal working dieduring a return stroke, a knock-out member remains extended while thepunch is withdrawn from a shell or can body thereby stripping the canbody from the punch. The knock-out member is then retracted into thepunch. By providing a round trip camming mechanism in combination with ageared knock-out drive mechanism, the knock-out stroke for the knockoutdrive is substantially equal to the height of the can and the knock-outmember is retracted into the punch before the return stroke iscompleted.

9 Claims, 5 Drawing Figures PATENTEDJAN 23 I973 SHEET 1 UF 3 PATENTEDJAN 23 I975 sum 2 or 3 APPARATUS FOR AND METHOD OF STRIPPING CONTAINERSFROM METAL WORKING PUNCIIES BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to a method of and apparatus fordrawing, sizing and/or wall ironing container bodies having integralbottom and side wall portions.

In the drawing, sizing and/or wall ironing of such containers, a punchcarrying a blank or cup cooperates with a die during a metal workingstroke of the punch. By utilizing a plurality of drawing and wallironing operations, a shell or container body of a type which may beutilized for beer or soft drinks or other products may be formed. Oncethe metal working stroke is completed, the container must be removedfrom the punch or the punch from the body.

2. Prior Art Various systems have been proposed and utilized in theprior art to remove the container bodies from the punch after the metalworking stroke is completed. These systems have fallen into twocategories: punch mounted strippers and die mounted strippers.

Punch mounted stripper systems rely upon the application of pressure onthe bottom of the container from the end of the punch. In mechanicalstripper systems of this type, a knockout member is extended from theend of the punch to move the container away from the end of the punch.In general, these mechanical stripper systems have been characterized bya rather short knock-out stroke which fails to reliably remove thecontainer from the punch.

In some cases, a pneumatic or hydraulic assist has been proposed. Thisinvolves the use of a fluid which is forced through the end of the punchto apply pressure on the container bottom which supplements the pressureprovided by the mechanical stripper. Even in these cases, removal of thecontainers from the punches has not been particularly reliable due tothe danger of can collapse or explosion. Furthermore, such systems havebeen expensive and incapable of meeting high speed container productionrequirements.

In other cases, ejection has been sought by the means of fluid alone asdisclosed in US. Pat. Nos. 3,423,985 Stolle et al. Such a system is alsounsatisfactory for the foregoing reasons.

Die mounted stripper systems providing a stripper jaw after the last diehave been added to the previously described punch mounted systems toincrease reliability. The jaw is designed to prevent a return of thecontainer once the container is past the jaw. Although this is effectiveas a backup, it is not completely reliable in all instances due to theirregularities of height and the nature of caring incident to wallironing operations.

SUMMARY OF THE INVENTION It is one object of this invention to provide amethod of and apparatus for removing container bodies from metal workingpunches which is reliable.

It is another object of this invention to provide a method of andapparatus for removing container bodies from metal working punches whichis fast.

' In accordance with one important aspect of the invention, theknock-out means is provided with the knock-out stroke equal to asubstantial portion of the container body height to reliably remove thecontainer from the punch.

In accordance with another important aspect of the invention, theknock-out means is extended from and retracted into the punch during thereturn stroke so as to satisfy the high speed production requirementsnecessary for drawn or ironed can bodies e.g., beverage, aerosol, andothers.

In one embodiment of the invention, the ejector system comprises aknock-out means at the end of the punch and extendable therefrom tostrip the can from the punch and a knock-out drive means cooperatingwith the knock-out means for extending the knock-out means from the endof the punch. A round trip camming means cooperates with a cammed meanswhich is coupled to the knock-out drive means so as to extend and thenretract the knock-out means with respect to the punch. By providing anappropriate rise and fall portion in the round trip camming means andappropriate gearing in the knock-out drive means, a

knock-out stroke equal to or greater than a substantial portion of thecontainer body height is achieved. In addition, the knockout means maybe extended from and retracted into the punch during the return stroke.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional view of a presshaving a container stripper system embodying the invention with thepress shown at the beginning of the metal working stroke for the punch;

FIG. 2 is a simplified sectional view similar to FIG. 1 with the punchshown at the end of the metal working stroke and the beginning of thereturn stroke;

FIG. 3 is a simplified sectional view similar to FIGS. 1 and 2 with thepunch shown during the return stroke;

FIG. 4 is a sectional view of the ejector system taken along sectionlines 4--4 of FIG. 1; and

FIG. 5 is a sectional view of the ejector system taken along sectionlines 55 of FIG. 4.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT A press 10 for use informing containers such as beer or soft drink cans is shown in FIG. 1.The press comprises a metal working punch 12 which is secured to a ram14 by a chuck l6 and cooperates with at least one metal working dieelement 48 as shown in FIGS. 2 and 3. In accordance with this invention,a stripper system for removing drawn and/or wall ironed container bodiesor shells from the punch 12 is embodied in the press 10.

The stripper system comprises the following components: a knock-outmeans 18 coaxially and reciprocatingly mounted within the punch 12 whichmoves through a knock-out stroke to apply pressure to the bottom of thecontainers to effect stripping thereof; a knock-out drive means 20mounted on the ram I4 for driving the knock-out means 18 through theknock-out stroke; a cammed means 22 movable parallel to and transverselywith respect to the punch 12 and coupled to the knock-out means 20 foractuation thereof; and a round trip camming means 24 which is mounted ona fixed press frame member 26 so as to cam the cammed means 22.

Reference will now be made to FIGS. 1-3 in describing the generaloperation of the stripper system. As shown in FIG. 1, the punch 12 is inposition I at the top or beginning of a metal working stroke with thecammed means 22 located in a first linear portion 28 of a round tripcamming path 30. At the beginning of the metal working stroke for thepunch 12 and as long as the cammed means 22 remains in the first linearportion 28, a drive mechanism of the knock-out drive means isstationary. In particular, a rack 32, a small gear 34 engaged by therack 32, and a large gear 36 coupled to a small gear 34 through a shaft38 remain stationary.

As a consequence, a rack portion 40 of the knockout means 18 remainsstationary with respect to the gear 36 thereby maintaining a knock-outpad 42 and a connecting knock-out rod 44 retracted within the punch 12.The knock-out drive means 20 and the knock-out means 18 remain in thiscondition as the cammed means 22 enters and passes through a secondlinear portion 46 of the round trip camming path 30. When the cammedmeans 22 reaches the bottom of the second linear portion 46, as shown inpositions II and Ill in FIG. 2, the metal working stroke of the punch 12is completed. In position III, the container C has passed substantiallythrough the die element 48.

The return stroke of the punch 12 now begins simultaneously with theknock-out stroke of the knock-out means 18. During the initial portionof the punch return stroke, the cammed means 22 moves through a riseportion 50 of the round trip camming path 30 which communicates with thebottom of the second linear portion 46. As the cammed means 22 movesaway from the second linear path 46, the rack 32 which is coupled to thecammed means 22 also moves thereby rotating the gears 34 and 36 in aclockwise motion and forcing the rack gear portion 40 of the knock-outdrive means down. By providing the appropriate rate of rise for the riseportion 50 and an appropriate gear ratio for the gears 34 and 36, theknock-out pad 42 may remain substantially stationary with respect to thedie 48 as the punch 12 is removed from the die 48. In this manner, theknock-out pad 42 is extended toward the bottom of the punch 12 to anultimate position shown in FIG. 3 corresponding to position IV of thecammed means 22.

In accordance with one very important aspect of the invention, theknock-out pad 42 and the rod 44 are extended a distance substantiallyequal to the height of the container C. This assures complete separationof the container C from the punch 12 thereby providing reliable removalof the container C from the punch.

With the knock-out stroke now completed, the cammed means 22 enters afall portion 52 of the round trip camming path 30 as the return strokeof the punch 12 continues. At this time, the cammed means 22 moves upand to the right toward the first and second linear portions 28 and 46along with the rack 32 coupled thereto. This produces a counterclockwiserotation of the gears 34 and 36 resulting in the upward movement of therack gear portion 40 and the knockout pad 42. By the time the cammedmeans 42 has reached position V, and the juncture of portions 28 and 46,the return stroke of the knock-out pad 42 has been completed and theknock-out pad and the knock-out rod 44 have been entirely retractedwithin the punch 12.

In accordance with another very important aspect of the invention, theknock-out means travels at a rather rapid rate to assure completeretraction of the knockout pad 42 before the return stroke of the punch12 is completed. This is provided by a rather steep incline in the fallportion 52 in combination with the gear ratio between the gears 34 and36. Once the knock-out pad 42 and the rod 44 have been completelyretracted within the punch 12, the cammed means 22 moves from position Vthrough position VI and to position I as the return stroke is completed.Throughout this time, the rack 32, the gears 34 and 36, and the worminggear 40 remain stationary with respect to one another.

Detailed aspects of the stripper system will now be described withreference to FIGS. 4 and 5. It will be understood that the cammed means22 moves from position II to position III without any movement of therack 32. Similarly, the cammed means 22 moves from position V toposition VI without any transverse movement of the rack 32. This isachieved by the spring biased coupling 54 between the cammed means 22which comprises a head 56 of a bolt 58 mounted in a sliding block 60 andthe rack 32 having an axial bore 62 as best shown in FIG. 4. The springbiased coupling 54 comprises a rod 64 which is threadedly fastened tothe sliding block 60 and extends into the axial bore 62 with a helicalspring 65 located between the other end 66 of the rod 64 and one end 68of the rack 32.

By providing a spring biased coupling with the spring 64 in a state ofcompression with the cammed means 22 located in position II, the cammedmeans 22 is in effect pulled to position III without movement of therack 32. The knock-out pad 42 which engages a complementary conicalsurface 70 at the bottom of the punch 12 requires the block 60 to moverather than the rack 32. Similarly, relative movement of the worm gear40, gears 34 and 36, and the rack 32 is precluded so as to compress thespring 65 as the cammed means 22 reaches position VI and returns toposition I. In this manner, the cammed means 22 is spring loaded at thebeginning of each metal working stroke.

As also shown in FIGS. 4 and 5, the gears 34 and 36 comprise a unitarymember 72 rotatably mounted on a pin 74 which extends through oppositewall members 75 and 76 of the knock-out drive means 20 with a nut 78engaging a threaded portion 80 at the wall portion 74. As mentionedpreviously, the gear ratio between the gears 34 and 36 is properlychosen in view of the rise and fall of the round trip camming path 30 tomaintain the knock-out pad 30 substantially stationary with respect tothe die 48 at the beginning of the return stroke for the punch 12 andsubsequently moving the knock-out pad 42 at twice the speed of the punch12. Utilizing the camming contour comprising the rise portion 50 and thefall portion 52, a gear ratio of 2:1 for the gears 36 and 34 has beenfound particularly suitable.

Referring to FIG. 1, a spring biased lever 82 is shown at the junctureof the first linear portion 28, the second linear portion 46 and thefall portion 52. The lever 82 including an arm 84 is maintained in aposition shown in full during the metal working stroke of the punch 12by a spring 86 fastened to the block 88 of the camming means 24 by ascrew 90. This position is maintained during the metal working strokewhen the cammed means 22 moves from the first linear portion 28 to thesecond linear portion 46. The position shown in phantom results when thecammed means 22 moves from the fall portion 52 to the first linearportion 58 after completion of the knock-out stroke and during the endof the return stroke for the punch 12.

For purposes of simplification, a fragmentary portion of the pressincluding bearings 92 and bearing surfaces 94 associated with the ram 14are shown. It will be appreciated that various types of containerforming equipment well known in the art may embody the stripper systemof this invention. It will also be appreciated that the die element 48is merely representative of the die or plurality of dies which might beutilized in connection with the ejector system. Similarly, the punch 12is also representative. The stripper system may be utilized in a punchand die combination such as that shown in copending application Ser. No.62,791, filed Aug. 11, 1970, which is incorporated herein by reference.As shown in this application, the dies perform various drawing, sizingand wall ironing operations. Such a punch and die combination willproduce the containers disclosed in copending application Ser. No.57,124, filed July 22, 1970, which is also incorporated herein byreference.

While preferred forms and arrangements have been shown to illustrate theinvention, it will be understood that various changes may be madewithout departing from the spirit and scope of the invention as definedin the appended claims.

What is claimed is:

1. In an apparatus for drawing, sizing and/or wall ironing cans havingat least one die and a punch for carrying a blank or cup into metalworking engagement with said die and wherein said punch enters said dieduring a metal working stroke and is removed from said die during areturn stroke, said apparatus comprising a can stripper system forremoving said can from said punch comprising:

a knock-out means at the end of said punch and extendable therefrom toeject the can from said punch;

a knock-out drive means cooperating with said knock-out means forextending said knock-out means, from the end of said punch;

a cammed means coupled to said knock-out drive means and said punch andmovable with said punch in a direction parallel with the movement ofsaid punch during the metal working stroke and the return stroke; andround trip camming means for camming said cammed means in a directiontransverse to the movement of said punch during the metal working strokeand the return stroke so as to actuate said knock-out drive means toextend and then retract said knock'out means with respect to said punch.

2. The apparatus of claim 1 wherein said round trip camming meanscomprises a rise portion and a fall portion, said camming means movingalong said rise portion and then said fall portion during the returnstroke of said punch so as to extend said knock-out means and thenretract said knock-out means during the return stroke.

3. The apparatus of claim 2 wherein said knock-out drive means includesgear means, the combination of said rise portion of said camming meanswith said gear means rendering said knock-out means substantiallystationary with respect to said die as said cammed means is cammed bysaid rise portion during the return stroke thereby extending saidknock-out means from said punch and moving said knock-out means at amore rapid rate with respect to said die than said punch moves withrespect to said die as said cammed means is cammed by said fall portionduring the return stroke thereby retracting said knock-out means intosaid punch.

4. The apparatus of claim 2 wherein said knock-out drive means includesgear means, the combination of said rise portion and said fall portionof said camming means with said gear means producing a knock-out strokehaving a length equal to a substantial portion of the can height.

5. The apparatus of claim 2 wherein said knock-out means comprises arack portion; and said knock-out drive means comprises a rack coupled tosaid camming means and a gear means coupling said rack portion to saidrack, said rack extending transversely with respect to said knock-outmeans and said punch, movement of said rack resulting in movement ofsaid knock-out means.

6. The method of claim 5 wherein said gear means is characterized by aratio of 2:1 whereby said knock-out means moves at twice the speed ofsaid rack.

7. The apparatus of claim 6 wherein said knock-out drive means includesa spring means coupling said cammed means to said rack means, saidspring means biasing said cammed means so as to force said cammed meansto enter said rise portion of said camming means at the end of the metalworking stroke.

8. The apparatus of claim 7 wherein said round trip camming meansincludes a first linear portion receiving said cammed means during theearly portion of said metal working stroke and the latter portion ofsaid return stroke and a second linear portion receiving said cammedmeans during the latter portion of said metal working stroke, said riseportion communicating with said second linear portion and said fallportion communicating with said first linear portion and said secondlinear portion at the juncture therebetween.

9. The apparatus of claim 8 including a spring biased lever at saidjuncture, said lever being spring biased to force said cammed means tomove from said first linear portion to said second linear portion duringthe metal working stroke of said punch while permitting said cammedmeans to move from said fall portion to said first linear portion duringthe return stroke of said punch.

i i i i t

1. In an apparatus for drawing, sizing and/or wall ironing cans havingat least one die and a punch for carrying a blank or cup into metalworking engagement with said die and wherein said punch enters said dieduring a metal working stroke and is removed from said die during areturN stroke, said apparatus comprising a can stripper system forremoving said can from said punch comprising: a knock-out means at theend of said punch and extendable therefrom to eject the can from saidpunch; a knock-out drive means cooperating with said knock-out means forextending said knock-out means, from the end of said punch; a cammedmeans coupled to said knock-out drive means and said punch and movablewith said punch in a direction parallel with the movement of said punchduring the metal working stroke and the return stroke; and a round tripcamming means for camming said cammed means in a direction transverse tothe movement of said punch during the metal working stroke and thereturn stroke so as to actuate said knock-out drive means to extend andthen retract said knock-out means with respect to said punch.
 2. Theapparatus of claim 1 wherein said round trip camming means comprises arise portion and a fall portion, said camming means moving along saidrise portion and then said fall portion during the return stroke of saidpunch so as to extend said knock-out means and then retract saidknock-out means during the return stroke.
 3. The apparatus of claim 2wherein said knock-out drive means includes gear means, the combinationof said rise portion of said camming means with said gear meansrendering said knock-out means substantially stationary with respect tosaid die as said cammed means is cammed by said rise portion during thereturn stroke thereby extending said knock-out means from said punch andmoving said knock-out means at a more rapid rate with respect to saiddie than said punch moves with respect to said die as said cammed meansis cammed by said fall portion during the return stroke therebyretracting said knock-out means into said punch.
 4. The apparatus ofclaim 2 wherein said knock-out drive means includes gear means, thecombination of said rise portion and said fall portion of said cammingmeans with said gear means producing a knock-out stroke having a lengthequal to a substantial portion of the can height.
 5. The apparatus ofclaim 2 wherein said knock-out means comprises a rack portion; and saidknock-out drive means comprises a rack coupled to said camming means anda gear means coupling said rack portion to said rack, said rackextending transversely with respect to said knock-out means and saidpunch, movement of said rack resulting in movement of said knock-outmeans.
 6. The method of claim 5 wherein said gear means is characterizedby a ratio of 2:1 whereby said knock-out means moves at twice the speedof said rack.
 7. The apparatus of claim 6 wherein said knock-out drivemeans includes a spring means coupling said cammed means to said rackmeans, said spring means biasing said cammed means so as to force saidcammed means to enter said rise portion of said camming means at the endof the metal working stroke.
 8. The apparatus of claim 7 wherein saidround trip camming means includes a first linear portion receiving saidcammed means during the early portion of said metal working stroke andthe latter portion of said return stroke and a second linear portionreceiving said cammed means during the latter portion of said metalworking stroke, said rise portion communicating with said second linearportion and said fall portion communicating with said first linearportion and said second linear portion at the juncture therebetween. 9.The apparatus of claim 8 including a spring biased lever at saidjuncture, said lever being spring biased to force said cammed means tomove from said first linear portion to said second linear portion duringthe metal working stroke of said punch while permitting said cammedmeans to move from said fall portion to said first linear portion duringthe return stroke of said punch.